The use of automobiles and other vehicles for personal transportation, commerce and service has become firmly established. Most vehicles utilize inflatable tires as a significant element of the vehicle's design and function.
In the same way that a vehicle's engine or transmission must receive periodic maintenance, tires also must be regularly serviced to maintain optimal performance. Other than replacing tires when they become worn, maintaining the correct air pressure within a tire is the most important aspect of tire maintenance.
When the air pressure within a tire is either too high or too low, the tire cannot perform at its optimal level. Incorrect air pressure within a tire can also present a safety hazard, will lead to excessive and more frequent tire wear, and will require greater fuel consumption by the vehicle. Therefore, it is imperative that vehicle tire pressure be maintained at the proper level.
One of the most significant, yet often overlooked, contributors to tire air pressure fluctuations is temperature. It is often difficult to accurately determine if a tire pressure is correct when the temperature is effecting the pressure.
There are several factors that can generate temperature fluctuations on or around tires. These factors include: the environmental conditions, the tire condition, tires that have been driven for extended periods of time, vehicle brake components emitting heat, the weight of the vehicle and the condition of the road.
There are prior art devices and systems available for determining whether the air pressure within a tire is correct. Some examples are a simple hand-held gauge that is manually inserted into the tire valve, to complex electronic systems with sensors that operate in conjunction with a modern vehicle's computer diagnostic system. Unfortunately, most of these devices and systems do not consider temperature fluctuations when determining whether the air pressure is correct. It is obvious that a tire air pressure indicator that does recognize temperature fluctuations would be extremely beneficial.
A search of the prior art did not disclose any patents or industry literature that read directly on the claims of the instant invention. However, the following U.S. patents are considered related:
U.S. PAT. NO.INVENTORISSUED6,525,655Huang25 Feb. 20036,034,596Smith7 Mar. 20004,954,806Huang4 Sep. 19904,814,745Wang21 Mar. 19893,453,590Burgess1 Jul. 1969
The U.S. Pat. No. 6,525,655 discloses a diaphragm-type tire pressure indictor that is fastened to the air nozzle of a vehicle tire for indicating a low tire pressure. A flexible diaphragm is mounted in a receiving chamber in the casing of the tire pressure indicator. A spring-connected push rod is connected to the flexible diaphragm that indicates the status of the tire pressure of the vehicle tire.
The U.S. Pat. No. 6,034,596 discloses a system for displaying dynamic readings of a motor vehicle's tire pressure, temperature and tire ride efficiency. The system comprises individual integrated units that are attached to each valve stem. Each unit comprises a pressure sensor and a temperature sensor coupled to a microcontroller which activates a transmitter/receiver set with a measured signal. The signal is received by a transmitter/receiver set in a passenger compartment mounted display.
The U.S. Pat. No. 4,954,806 discloses a warning device for detecting inadequate tire air pressure. The device comprises an outer shell which includes all assembly members and can be screwed into a tire's air valve. A needle plate which operates and opens the tire valves, a resilient hook undertakes a compression from the tire air pressure; a switch bar moves along with the resilient hook under compression; and a PC board with the warning sounds and lights circuit. As screwedly mounted to each tire valve of a vehicle's, this device because of function of the operating needle plate can allow air communication and thus make the air pressure in the resilient hook outer front area equal to tire's regulated air pressure, and that acts resilient hook to move the switch bar which then causes the warning sounds and lights circuit to be open circuit. When the tire air pressure of the tire valve falls below a predetermined standard or electrical generates warning sounds and lights.
The U.S. Pat. No. 4,814,745 discloses a combined cap and signal device that is attached to a tire after the tire is inflated. The device includes an electric alarming unit mounted in a cap-like casing with an adapter that is connected to an inflating valve of the tire. A resilient disc is disposed in the adapter that is forced by air so that the disc causes the alarming unit to open when the tire is not deflated.
The U.S. Pat. No. 3,453,590 discloses a system for detecting the presence of low pressure in a vehicle tire. A signal generator in the form of a turbine is provided along with a low pressure valve in a tire valve stem. When the tire pressure falls below a certain value the low pressure valve opens and the escaping air drives the turbine. The turbine either generates a sound wave or drives an electromagnetic generator to generate a high frequency induction field. A detector on the vehicle senses the presence of such a signal, and in turn activates an alarm to inform the driver of the low pressure condition.
For background purposes and as indicative of the art to which the invention is related reference may be made to the following remaining patents located in the search.
U.S. PAT. NO.INVENTORISSUED5,289,161Huang22 Feb. 19944,954,806Huang4 Sep. 19904,737,760Huang, et al12 Apr. 1988